As light-sensitive substances which are solubilized by irradiation with actinic light rays, or which are of so-called "positive-working" type, there have conventionally been known o-quinonediazide compounds, which have actually been widely used for preparing lithographic printing plates, photoresists, etc. Examples of such o-quinonediazide compounds are described in many publications including U.S. Pat. Nos. 2,766,118, 2,767,092, 2,772,972, 2,859,112, 2,907,665, 3,046,110, 3,046,111, 3,046,115, 3,046,118, 3,046,119, 3,046,120, 3,046,121, 3,046,122, 3,046,123, 3,061,430, 3,102,809, 3,106,465, 3,635,709, 3,647,443, etc.
Such o-quinonediazide compounds are decomposed upon irradiation with actinic light rays to form five-membered carboxylic acids, and thus become alkali solution soluble are utilized. However, all of them have the defect that they possess only insufficient light sensitivity. This is attributed to the fact that, with o-quinonediazides, the quantum yield essentially cannot exceed 1.
Various attempts have so far been made to raise light sensitivity of a light-sensitive composition containing the o-quinonediazide compound. However, it has been extremely difficult to raise light sensitivity while keeping development latitude at the same level upon development. Examples of such attempts are described in Japanese Patent Publication No. 12242/73 (corresponding to U.S. Pat. No. 3,661,582 and DE No. 2,028,214), Japanese Patent Application (OPI) No. 40125/77 (corresponding to U.S. Pat. No. 4,009,033) (The term "OPI" as used herein refers to a "published unexamined Japanese patent application"), U.S. Pat. No. 4,307,173, etc.
Recently, several proposals have been made as to positive-working light-sensitive composition without using o-quinonediazide compounds. As one example thereof, there is illustrated polymer compounds having an o-nitro-carbinol ester group, described in Japanese Patent Publication No. 2696/81 (corresponding to U.S. Pat. No. 3,849,137 and DE No. 2,150,691). With the compounds, too, however, very high light sensitivity is not attained due to the same reason as with the o-quinonediazides. Apart from this, as a process for raising light sensitivity using a light-sensitive system which is activated by catalytic action, there has been applied a known principle of causing a second reaction with an acid produced by photolysis, to thereby solubilize exposed areas.
Examples of applying this principle include a combination of a compound capable of producing an acid upon photolysis and an acetal or O,N-acetal compound (Japanese Patent Application (OPI) No. 89003/73, U.S. Pat. No. 3,779,778 and DE No. 2,306,248), a combination with an orthoester or amidoacetal compound (Japanese Patent Application (OPI) No. 120714/76, U.S. Pat. No. 4,101,323 and DE No. 2,610,842), a combination with a polymer having acetal or ketal group in the main chain (Japanese Patent Application (OPI) No. 133429/78, U.S. Pat. No. 4,247,611 and DE No. 2,718,254), a combination with an enol ether compound (Japanese Patent Application (OPI) No. 122995/80, U.S. Pat. No. 4,248,957 and DE No. 2,829,511), a combination with an N-acyliminocarbonic acid compound (Japanese Patent Application (OPI) No. 126236/80, U.S. Pat. No. 4,250,247 and DE No. 2,829,512), and a combination with a polymer having orthoester group in the main chain (Japanese Patent Application (OPI) No. 17345/81, U.S. Pat. No. 4,311,782 and DE No. 2,928,636). Since these compounds principally provide a quantum yield of more than 1, there is a possibility of showing a high light sensitivity. However, with the acetal or O,N-acetal compounds and the polymer having acetal or ketal group in the main chain thereof, the rate of the second reaction to be caused with an acid produced by photolysis is so slow that they do not show an enough light sensitivity to be actually used. The ortho ester or amidoacetal compound, the enol ether compound, and the N-acyliminocarbonic acid compound have poor stability with time, and cannot be stored for a long time, although they do provide a high light sensitivity. Polymers having orthoester group in the main chain thereof have the defect that they possess only a narrow development latitude upon development, although they also provide a high light sensitivity.